This invention relates to a process for selectively sorbing residual thiophene-type contaminants from gasoline using a silver-exchanged faujasite-type crystalline molecular sieve as the adsorbent.
The separation of thiophene from benzene, especially where thiophene is present as a trace or minor impurity, is well known as being a difficult separation. The selective separation of thiophene-type contaminants from gasoline, which normally has a substantial content of benzene and substituted benzene is, of course, also a difficult separation. Thiophenes are also one of the most, if not the most, difficult of impurities to remove from gasoline by conventional hydrotreatment of gasoline stocks. They are known to be present in minor yet significant amounts in gasoline stocks even after such a treatment.
It is an object of this invention to provide a non-hydrogenative (no added hydrogen gas) process for effectively removing thiophene-type contaminants from gasoline.